1、June 2007DEUTSCHE NORM English price group 14No part of this standard may be reproduced without prior permission ofDIN Deutsches Institut fr Normung e. V., Berlin. Beuth Verlag GmbH, 10772 Berlin, Germany,has the exclusive right of sale for German Standards (DIN-Normen).ICS 71.040.40; 81.080!,y69“98
2、61922www.din.deDDIN EN 12698-1Chemical analysis of nitride bonded silicon carbide refractories Part 1: Chemical methodsEnglish version of DIN EN 12698-1:2007-06Chemische Analyse von feuerfesten Erzeugnissen aus nitridgebundenem Siliciumcarbid Teil 1: Chemische VerfahrenEnglische Fassung DIN EN 12698
3、-1:2007-06www.beuth.deDocument comprises 34 pages 09.07DIN EN 12698-1:2007-06 2 National foreword This standard has been prepared by CEN/TC 187 “Refractory products and materials” (Secretariat: BSI, United Kingdom). The responsible German body involved in its preparation was the Normenausschuss Mate
4、rialprfung (Materials Testing Standards Committee, Technical Committee NA 062-02-64 AA Chemische Analyse von nichtoxidischen keramischen Roh- und Werkstoffen. The DIN Standards corresponding to the International Standards referred to in clause 2 of the EN are as follows: ISO 3310-1 DIN ISO 3310-1 IS
5、O 5725-1 DIN ISO 5725-1 ISO 8656-1 DIN 51061-2, DIN EN 1402-2 National Annex NA (informative) Bibliography DIN 51061-2, Sampling of ceramic raw materials and refractory unmoulded products DIN EN 1402-2, Unshaped refractory products Part 2: Sampling for testing DIN ISO 3310-1, Test sieves Technical r
6、equirements and testing Part 1: Test sieves of metal wire cloth DIN ISO 5725-1, Accuracy (trueness and precision) of measurement methods and results Part 1: General principles and definitions EUROPEAN STANDARDNORME EUROPENNEEUROPISCHE NORMEN 12698-1March 2007ICS 71.040.40English VersionChemical anal
7、ysis of nitride bonded silicon carbide refractories -Part 1: Chemical methodsAnalyse chimique des produits rfractaires contenant ducarbure de silicium liaison nitrure - Partie 1: MthodeschimiquesChemische Analyse von feuerfesten Erzeugnissen ausnitridgebundenem Siliciumcarbid - Teil 1: ChemischeVerf
8、ahrenThis European Standard was approved by CEN on 15 February 2007.CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this EuropeanStandard the status of a national standard without any alteration. Up-to-date lists and bibliographical
9、 references concerning such nationalstandards may be obtained on application to the CEN Management Centre or to any CEN member.This European Standard exists in three official versions (English, French, German). A version in any other language made by translationunder the responsibility of a CEN memb
10、er into its own language and notified to the CEN Management Centre has the same status as theofficial versions.CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland,France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Lat
11、via, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal,Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.EUROPEAN COMMITTEE FOR STANDARDIZATIONCOMIT EUROPEN DE NORMALISATIONEUROPISCHES KOMITEE FR NORMUNGManagement Centre: rue de Stassart, 36 B-1050 Brussels
12、 2007 CEN All rights of exploitation in any form and by any means reservedworldwide for CEN national Members.Ref. No. EN 12698-1:2007: EEN 12698-1:2007 (E) 2 Contents Page Foreword .3 1 Scope 4 2 Normative references4 3 Terms and Definitions.4 4 Methods for determination .4 5 Sampling.5 6 Determinat
13、ion of free aluminium .5 6.1 Principle5 6.2 Reagents.6 6.3 Apparatus .6 6.4 Sample preparation .6 6.5 Procedure .6 6.6 Calculation and expression of results.6 7 Determination of total nitrogen7 7.1 General .7 7.2 Determination of total nitrogen by carrier gas fusion (CGF) 7 7.3 Determination of tota
14、l nitrogen content by fusion decomposition 10 7.4 Determination of total nitrogen content by Kjeldahl distillation 14 7.5 Determination of total nitrogen by microwave digestion16 8 Determination of free silicon 18 9 Determination of free silica 18 9.1 Principle18 9.2 Reagents.18 9.3 Apparatus .19 9.
15、4 Sample preparation .19 9.5 Procedure .19 9.6 Determination.21 9.7 Calculation and expression of SiO2content.21 9.8 Precision.21 10 Determination of carbon .21 10.1 Determination of the total carbon, Ct21 10.2 Determination of free carbon, Cfree21 11 Calculation of silicon carbide content.25 12 Det
16、ermination of free alumina (Al2O3) .25 12.1 Principle25 12.2 Reagents.25 12.3 Apparatus .26 12.4 Procedure .26 12.5 Calculation and expression of results.26 12.6 Precision.26 Annex A (informative) Determination of free carbon using the hot chromic sulfuric iodic acid method (10.2.1): Explanation for
17、 the evaluation of the different possible detection methods27 A.1 Coulometric detection system .27 A.2 Infrared absorption detection system .29 A.3 Conductometric detection system.30 Bibliography32 EN 12698-1:2007 (E) 3 Foreword This document (EN 12698-1:2007) has been prepared by Technical Committe
18、e CEN/TC 187 “Refractory products and materials”, the secretariat of which is held by BSI. This European Standard shall be given the status of a national standard, either by publication of an identical text or by endorsement, at the latest by September 2007, and conflicting national standards shall
19、be withdrawn at the latest by September 2007. According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germa
20、ny, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom. EN 12698-1:2007 (E) 4 1 Scope This standard describes the methods for the analysis of all refractory
21、products containing nitride and oxynitride bonded silicon carbide, irrespective of the silicon carbide level. It includes details of sample preparation, general principles of chemical analysis and detailed methods for the determination of carbon, silicon carbide, free aluminium, free silicon, total
22、nitrogen and oxygen. 2 Normative references The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. EN 12
23、475-4:1998, Classification of dense shaped refractory products Part:4 Special products EN 12698-2, Chemical analysis of nitride bonded silicon carbide refractories Part 2: XRD methods prEN ISO 21068, Chemical analysis of silicon carbide containing raw materials and refractory products ISO 836:2001,
24、Terminology for refractories ISO 3310-1, Test sieves Technical requirements and testing Part 1: Test sieves of metal wire cloth ISO 5022, Shaped refractory products Sampling and acceptance testing ISO 5725-1, Accuracy (trueness and precision) of measurement methods and results Part 1: General princi
25、ples and definitions ISO 8656-1, Refractory products Sampling of raw materials and unshaped products Part 1: Sampling scheme 3 Terms and Definitions For the purposes of this document the terms and definitions given in ISO 836:2001, EN 12475-4:1998 and the following apply. 3.1 nitride and oxynitride
26、bonded silicon carbide refractories refractory products predominantly consisting of silicon carbide with minor amounts of nitride phases as a matrix component NOTE In general, metallic silicon is used as precursor material which undergoes a phase transformation in an oxygen-free nitrogen atmosphere.
27、 4 Methods for determination A list of methods and the relevant European Standards are given in Table 1. Carbon is determined by the evolution of carbon dioxide on combustion in a stream of oxygen at defined temperatures. Silicon carbide is calculated by the difference of total carbon (Ctotal) and f
28、ree carbon (Cfree). NOTE 1 The carbon dioxide evolved can be conveniently measured coulometrically, gravimetrically by absorbtion onto soda lime, or by infrared detection. EN 12698-1:2007 (E) 5 Free aluminium is determined by the evolution of hydrogen on treatment with hydrochloric acid and by measu
29、ring the gas volume in a nitrometer. Free silicon shall be determined on the same sample by treatment with sodium hydroxide. Total nitrogen is determined by a variety of methods: carrier gas fusion, alkaline fusion, Kjeldal distillation or microwave digestion. NOTE 2 The nitrogen can be conveniently
30、 measured by thermal conductivity or after digestion as ammonium by titration with hydrochloric acid. Distinction between aluminium nitride and silicon nitride is made by their reaction with sodium hydroxide solution; aluminium nitride is quantitatively decomposed yielding free ammonia, while silico
31、n nitride is unaffected. A convenient commercial apparatus for determining total oxygen consists of an induction furnace in which the sample is heated with pure carbon. Carbon dioxide and carbon monoxide are measured by infrared absorption and the integrated signals are combined to give the total ox
32、ygen content. NOTE 3 Specification of many of the constituents can often be made using XRD techniques, e.g. free silicon, silicon nitride, silicon oxynitride, quartz and cristobalite (see EN 12698-2). Table 1 Methods and relevant European Standards Item tested European Standard Carbon and silicon ca
33、rbide prEN ISO 21068 Free silicon prEN ISO 21068 Oxygen prEN ISO 21068 Free aluminium EN 12698-1 Total nitrogen EN 12698-1 Silicon nitride/oxynitride, free silica EN 12698-1 XRD prEN ISO 21068 and EN 12698-2 Sialon EN 12698-Free carbon prEN ISO 21068 or EN 12698-1 Total carbon prEN ISO 21068 Silicon
34、 carbide prEN ISO 21068 and EN 12698-1 Free alumina EN 12698-1 5 Sampling Sample shaped and unshaped products using the procedures given in ISO 5022 and ISO 8656-1. When sampling large fragments, take care to collect samples from different points of individual pieces. Homogenize the sample by reduci
35、ng the maximum particle size to 150 m and take the test sample from this material. 6 Determination of free aluminium 6.1 Principle The volume of hydrogen generated by the action of dilute hydrochloric acid on any free aluminium in a sample is measured. EN 12698-1:2007 (E) 6 If the sample is known to
36、 contain carbonate, then the volume of hydrogen evolved is corrected for the known carbonate content. The free aluminium content can also be determined by the evolution of hydrogen using sodium hydroxide. In this case, the volume of hydrogen evolved is corrected for the silicon content. Free iron wi
37、ll also evolve hydrogen; a correction is made for the iron content. 6.2 Reagents During the analysis, unless otherwise stated, use only reagents of recognized analytical grade 6.2.1 Distilled water or water which has been fully demineralized by ion exchange (deionized water) and reagents of analytic
38、al grade. 6.2.2 Dilute hydrochloric acid, 1+1 by volume. 6.3 Apparatus 6.3.1 Nitrometer, as used for determining free silicon. 6.3.2 Balance, capable of reading to the nearest 0,1 mg. 6.4 Sample preparation Dry the test sample (sampling as described in clause 5) a to constant mass at (110 10) C for
39、a minimum of 2 h prior to analysis. 6.5 Procedure Weigh (0,5 0,01) g of sample into a clean, dry nitrometer tube. Place a dry ignition tube inside the tube and holding the nitrometer tube upright, introduce, using a long dropping pipette and without letting any touch the sample, 5 ml of dilute hydro
40、chloric acid into the ignition tube. Carefully fit the bung of the apparatus making sure there is good seal. Equalize the pressure and leave the three-way tap in a position that connects the sample and graduated tube. Tip the acid out of the ignition tube onto the sample. Shake the apparatus gently
41、and allow it to stand for 15 min. Read off the volume after equalizing the pressure. Shake gently and read again after another 5 min to 10 min. Record the final volume reading when consecutive readings are the same. Also note the temperature and barometric pressure. NOTE If this method is used frequ
42、ently, it is recommended that a conical flask with airtight sample insert device, e.g. a side-on positioned ground-in connection and ground-in stopper with weighing bottle (special version) is used. The weighed sample is placed into the stopper-connected weighing bottle. The hydrochloric acid is add
43、ed to the flask. After equalizing the pressure, the sample powder is added to the acid by turning the stopper. 6.6 Calculation and expression of results Correct the volume reading to the gas volume at standard temperature, V(STP)in ml, using equation (1): EN 12698-1:2007 (E) 7 ()( )()TppVV+=27327301
44、3,251OH1STP2(1) where V1is the measured volume, in ml; p is the atmospheric pressure, at time of measurement, in hPa; OH2p is the partial pressure of water vapour at the measured temperature, in hPa; T is the measured temperature, in C. Calculate the percentage of free aluminium, A, using equation (
45、2): ()mVA1008040,000STP= (2) where m is the mass of the sample, in g. Report the result to the nearest 0,1 %. 7 Determination of total nitrogen 7.1 General To determine total nitrogen one of the four methods given in 7.2 to 7.5 shall be used. 7.2 Determination of total nitrogen by carrier gas fusion
46、 (CGF) 7.2.1 General This method is used to determine nitrogen in silicon nitride, Si3N4, and other compounds, in the form of nitrides and oxynitrides by thermal decomposition. 7.2.2 Principle A sample, prepared as described in clause 5, is decomposed in a graphite crucible in a stream of carrier ga
47、s (helium) by heating it to above 2 400 C in a resistance furnace (electrode furnace). The gases released are mainly nitrogen, carbon monoxide and hydrogen. The carbon monoxide and hydrogen are oxidized to carbon dioxide and water and then removed by absorption. Alternatively, formed carbon monoxide
48、 and gases other than nitrogen shall be removed, for example, using a molecular sieve. The change in thermal conductivity due to the nitrogen component is then measured. The details of the determination procedure can vary with the type of apparatus used and it is therefore only possible to give gene
49、ral instructions that can be used with any type of apparatus. Using the gas calibration, the validity of the results is confirmed by analysing a reference material having similar extraction behaviour. EN 12698-1:2007 (E) 8 7.2.3 Reagents During the analysis, unless otherwise stated, use only reagents of recognized analytical grade. 7.2.3.1 Distilled water, or water which has been fully demineralized by ion exchange (deionized water). 7.2.3.2 Helium, having a minimum purity of 99,99 %. 7.2.3.3 Nitrogen, having a minimum of 99,99
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